Macadamia tetraphylla
L.A.S.Johnson.
Queensland Nut, Macadamia nut
(c) Pete Woodall, some rights reserved (CC BY-NC), uploaded by Pete Woodall
(c) Craig Robbins, some rights reserved (CC BY-NC), uploaded by Craig Robbins
What to Eat
Edible parts: Oil, Seed
Milk Oil. Seed - raw or cooked. Pleasantly flavoured and nutritious, the seed is a little sweeter than the related Macadamia integrifolia and contains a little less oil. They can be eaten as a dessert nut and can also be ground into a flour and then mixed with cereal flours to enrich the protein content. The shell is very hard, making it difficult to extract the seed. The seed is up to 30mm long and 24mm wide. The seed contains up to 72% of a high grade oil. This oil is seldom extracted due to the high value of the seed.
Where to Find It
Australia - New South Wales, Queensland.
AUSTRALASIA: Australia, New South Wales (northeast), Queensland (southeast),
How to Identify
Macadamia tetraphylla is an evergreen Tree growing to 10 m (32ft) by 10 m (32ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 9 and is frost tender. It is in leaf all year. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. The plant is self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil.
How to Grow
Macadamia tetraphylla succeeds in cool tropical or subtropical climates - in Australia they fruit well even when growing at least as far south as Sydney. In the tropics the plant fruits best at elevations from 1,000 - 1,500 metres. It grows best in areas where annual daytime temperatures are within the range 14 - 28°c, but can tolerate 8 - 38°c. When dormant, the plant can survive temperatures down to about -2°c, but young growth can be severely damaged at -1°c. The plant can survive slight frosts, though cold weather can result in the loss of the entire crop. It prefers a mean annual rainfall in the range 1,250 - 2,000mm, but tolerates 850 - 3,000mm. Plants grow best in rich moist but well-drained soils and a position in full sun. They require copious summer watering in their early stages. Prefers a pH in the range 5.5 - 7, tolerating 4.5 - 8. Trees require a sheltered position and are easily damaged by strong winds. Plants are slow growing in cultivation, seedlings take 6 - 7 years to produce their first fruit. The trees then produce commercial crops for about 40 - 50 years and can fruit for up to 100 years. There are some named varieties. Plants are self-fertile but yield better if cross-pollinated. Pruning is not normally necessary, but is tolerated if carried out in the autumn.
Propagation: Seed - best sown as soon as it is ripe in a nursery bed. The dehusked seed germinates quickly at 25°c. Cultivars may be grafted. Side wedge grafting has been used exclusively in Hawaii.
Other Uses
Cosmetic Fuel Oil Plant breeding Tannin. Agroforestry Uses: The decomposed husk is commonly used in potting soil. Other Uses: Macadamia shells may be used as fuel, generating sufficient energy to dry wet, in-shell nuts. The oil from the seed is used in cosmetics. The green seed hulls contain approximately 14% of tannins. The tree is used as a rootstock for M. Integrifolia.
Names & Synonyms
Queensland Nut, Bopple nut, Mukandania
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